knoop hardness of self-etch adhesives applied on superficial and deep dentin

Statement of the problem: low ph of self-etch adhesives might cause suboptimal polymeri-zation. purpose: this study aimed to evaluate the effect of dentin depth (deep and superficial) on polymerization efficacy of two self-etch adhesives, with different ph by means of knoop hardness test. materials and method: in this in vitro study, sixty sound molars were used to prepare 30 superficial dentin and 30 deep dentin specimens. dentin specimens of each depth were ran-domly distributed into two equal subgroups (n=15) and bonded by either adper prompt l-pop (strong self-etch adhesive) or adper easy bond (mild self-etch adhesive). knoop hardness test was employed to evaluate degree of cross-linking of the adhesives. data were analyzed with spss 16, using two-way anova to compare mean hardness values of the study groups (p< 0.05). results: there was no interaction effect between dentin depth and the type of adhesive (p= 0.36). regardless of dentin depth, hardness of adper easy bond was significantly higher than that of adper prompt l-pop (p< 0.001). moreover, both the adhesives showed higher hardness when bonded to superficial dentin compared to deep dentin (p< 0.001). conclusion: degree of cross-linking of the self-etch adhesive with mild acidity was more than that of the strong self-etch adhesive after light-curing. surface hardness of both adhesives was higher on superficial dentin compared to deep dentin